Sulphureus brown cubical rot

• French disease name: Carie brune cubique à Laetiporus sulphureus
• Pathogen name: Laetiporus sulphureus (Bull.:Fr.) Murrill
• Kingdom: Fungi
• Phylum: Basidiomycota
• Class: Agaricomycetes
• Order: Polyporales
• Family: Laetiporaceae
• Partial list of synonyms:
  • Polyporus sulphureus (Bull.: Fr.) Fr.
  • Sporotrichum versisporum (C.G. Lloyd) Stalpers

Distribution

• Canada

Damage, symptoms and biology

In eastern Canada, the bright orange-yellow fruiting bodies generally appear in July. They turn white and then break up starting in August.

Fruiting bodies are often not formed until years after the fungus is well established, so when present, they indicate significant internal defect. The rot is generally restricted to the butt log. When present in recreation sites, infected trees should be considered hazardous and should be removed.

Other information

The decay caused by L. sulphureus is similar to that of Fomitopsis officinalis, but the mycelial felts are not bitter. Laetiporus sulphureus is commonly harvested as an edible fungus, easily identified by the morphology and bright yellow colour of its fruiting bodies. On conifers, the fruiting bodies of Laetiporus huroniensis Burd. & Banik are often confused with those of L. sulphureus.

Canadian Forest Service Publications

Sulphureus brown cubical rot

Information on host(s)

Main host(s)

• Butternut
• Garry oak
• Red oak
• Sitka spruce
• Western hemlock
• White ash

Secondary host(s)

• Amabilis fir
• American chestnut
• Ashes
• Birch
• Black cherry
• Elms
• Maple
• Ponderosa pine
• Poplars / aspens / cottonwoods
• Rocky Mountain Douglas-fir
• Shore pine
• Spruces
• Subalpine fir
• Western redcedar
• Western white pine
• Willow

Photos

Fruiting bodies of L. sulphureus

Alan Stewart

Fruiting bodies of L. sulphureus

Eric Allen

Brown cubical rot symptom caused by L. sulphureus

J. Brown

White mycelial felts associated with decay

Rollie Banyard